My smallest coin that I own is the 12mm 1-1/2 pence issue shown here: http://www.cointalk.com/attachments/dsc_0016-jpg.279236/ http://www.cointalk.com/attachments/dsc_0015-jpg.279231/
smallest coin I have is a panama pill 10 MM size. of wait... I have 2-3 way smaller coins from Tranvencore India 2-3MM in size. pics later when i find them.
How would you even pick those up? 2mm is on the scale of the tip of a fine point Sharpie pen, I think.